WATSON-WATT, SIR ROBERT ALEXANDER

born April 13, 1892, Brechin, Forfarshire , Scot. died Dec. 5, 1973, Inverness, Inverness-shire Scottish physicist credited with the development of radar in England. Watson-Watt attended the University of St. Andrews and later taught at University College, Dundee. From 1915 to 1952 he held a number of government positions, beginning as a meteorologist working on devices for locating thunderstorms. In 1935, while heading the radio department of the National Physical Laboratory, he began work on aircraft radio-location. By late 1935 he was able to locate planes at a distance of 110 km (70 miles) by beaming radio waves at them, receiving their reflections from the airplanes, and calculating distance by elapsed time. This work led to the design of the world's first practical radar system, which was a vital element in the defense of Britain against German air raids in 1940. He was knighted in 1942. Watson-Watt's other contributions include a cathode-ray direction finder used to study atmospheric phenomena, research in electromagnetic radiation, and inventions used for flight safety.